Note: Descriptions are shown in the official language in which they were submitted.
WO 95/01817 PCT/US94/07431
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CONTOURED LANDING SURFACE :iYSTEMS
' AND METHOD OF MAKING THEREOF
TECIf~IICAL FIELD
The present invention relates generally to
landing surfaces for use in athletics and more
particularly to landing surface systems which are
capable of compensating for variables such as
velocity, mass and surface area at the point of
impact for each individual athlete.
BACKGROUND OF THE INVENTION
Landing surfaces or pits are well-known in the
prior art. For example, it is well-)~;nown to
construct a landing pit so as to decrease
deceleration of the athlete's descending body in
order to minimize or at least reduce risk of injury.
One construction well known in the art is the
honeycomb structure. The honeycomb construction
typically includes a piece of foam enclosed in a
protective layer or cover. The foam has openings or
holes in various positions which allow for
displacement of air upon impact to break the fall of
the athlete. However, the force of impact is
absorbed in the landing surface at the point of
impact rather than being distributed throughout the
entire construction.
These structures have been insufficient due to
"jarring effects" or "bottoming out" by the user.
Attempts to remedy this problem have included
constructing landing pits with a combination of foam
sections or layers having various densities. For
example, one foam section may be included for
comfort, while another, having a different density,
may be utilized to prevent the athlete from
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bottoming out. Still another channeled section
having yet another density may be employed to
regulate the flow of air that is expelled upon
impact. However, such structures do not account for
individual disparities in velocity, mass or surface
area upon impact. Rather, prior art constructions
have generally been constructed based on an average
of variables of the typical users.
Consequently, slower and/or lighter athletes
still experience a "jarring effect" as the landing
surface does not expel enough air. In contrast, a
heavier and/or faster athlete often experiences a
feeling of "bottoming out". This is attributable to .
the athlete's surpassing the normal or average
expectancy of foam compression. Similar problems
occur in the area of high jump and pole vault events
where there are substantial variations in heights
descended from. Further, these structures do not
provide a single density unit which is capable of
both controlling deceleration, while simultaneously
compensating for a multitude of variables on an
individual basis.
Another disadvantage associated with the prior
art occurs when two or more types of foam are
laminated together. For example, typical prior art
constructions utilize a lesser grade of foam having
a smaller density as the top layer. For instance, a
1.2 lb/ft3 top layer placed on 1.5 lb/ft3 is
available. However, the difference in foam
properties frequently causes the top layer to
degrade more rapidly than the underlying layer,
thereby reducing the product life of the landing
surf ace .
Still another disadvantage found in the prior
art is the presence of large air channels in the
structure. Large air channels lack accuracy and
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selectivity in displacing air. As a result of the
larger openings or holes present in prior art
constructions, deceleration and comfort of the
athlete are sacrificed.
It would therefore be desirable to provide a
single density landing surface system which is
capable of compensating for many variables without
the necessity of combining a variety of different
density foam sections in order to overcome the
problems associated with the prior art.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a contoured
landing surface system which achieves controlled
deceleration of an athlete's descending body while
simultaneously compensating for velocity, mass and
surface area at the point of impact. The invention
utilizes a multi-layer structure which includes a
network of ridges and air channels designed to
respond to the force generated by an athlete's
falling body, thereby providing a smaother, safer
and more comfortable landing than achieved using
prior art techniques. As will become apparent
below, it has now been discovered that a landing
surface having smaller, but more numerous openings
provides benefits over a surface having larger but
fewer openings, even if the total volume for
expelled air remains the same.
It is thus an object of the present invention
to provide a contoured landing surface system.
It is another object of the present invention
to provide a contoured landing surface which
functions primarily based on the displacement of air
rather than on foam characteristics.
It is yet another object of the present
invention to provide a contoured landing surface
which does not bottom out upon impact, yet
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compresses sufficiently to avoid a jarring effect to
the user.
It is a further object of the present invention
to provide a contoured landing surface which
completely and comfortably compensates for variables
such as velocity, mass and surface area at the ~>oint
of impact and automatically accounts for differE:nces
in such variables on an individual bases.
It is still a further object of the present.
invention to provide a single density landing
surface system which ensures a smoother landing than
honeycomb designs or mufti-density structures.
It is still a further object of the present.
invention to provide a method of making a contoured
landing surface system capable of accomplishing the
aforementioned objects.
In accordance with one aspect of the present
invention there is provided a landing surface block
for use in athletics having a longitudinal axis and
a transverse axis, comprising: a top layer formed
from a single piece of compressible material having
top and bottom surfaces, the bottom surface of the
top layer having a plurality of ridges oriented
along the transverse axis of the landing surfacE: and
defining a plurality of spaces therebetween; at
least one middle layer having top and bottom
surfaces, each surface of the middle layer having a
plurality of ridges oriented along the longitudinal
axis of the landing surface and defining a plurality
of spaces therebetween, the top surface of the
middle layer positioned below the bottom surface of
the top layer and attached thereto to define a f-first
network of air channels along the longitudinal and
the transverse axes of the landing surface between
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the top and middle layers; a bottom layer formed
from a single piece of material having top and
bottom surfaces, the top surface of the bottom layer
having a plurality of ridges oriented along the
transverse axis of the landing surface and defir_ing
a plurality of spaces therebetween, the top surface
of the bottom layer positioned below the bottom
surface of the middle layer and attached thereto to
define a second network of air channels along the
longitudinal and the transverse axes of the landing
surface between the middle and bottom layers;
wherein the first and second networks displace a
volume of air in response to an applied landing
force to cushion the applied landing force.
In accordance with another aspect of the
present invention there is provided a landing
surface for use in athletics having a longitudinal
axis and a transverse axis, the landing surface
comprising: a first layer formed from a single
piece of compressible material having top and bottom
surfaces, the bottom surface having a plurality of
ridges and air channels formed between the ridges,
the ridges and air channels oriented along the
transverse axis of the landing surface; a second
layer formed from a piece of single density material
having top and bottom surfaces, the top surface
having a plurality of ridges and air channels formed
between the ridges, the ridges and air channels
oriented along the longitudinal axis of the landing
surface, the top surface positioned on the bottom
surface of the first layer and attached thereto;
means for adhering the first layer to the second
layer; and a cover enclosing the first and second
layers, the cover having side and bottom surfaces
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formed of a non-breathable material and a top
surface formed of a breathable material, wherein
compression of the first and second layers expels
air from the air channels and upward through the top
surface.
In accordance with yet another aspect of the
present invention there is provided a method of
making a landing surface block having a longitudinal
axis and a transverse axis including a first layer
formed from a single piece of compressible material
having top and bottom surfaces, the bottom surface
of the first layer having a plurality of ridges
oriented along the transverse axis of the landing
surface and defining a plurality of spaces
therebetween, comprising: forming at least one set
of contours in the block along the transverse axis
to create first and second layers, each layer having
top and bottom surfaces; separating the first and
second layers from one another such that the bottom
surface of the first layer and the top surface of
the second layer each have a plurality of ridges and
air channels formed on the surfaces thereof, the
ridges and air channels of the first layer
positioned along the transverse axis; separating the
second layer into at least two pieces, each piece
having a first end and a second end; aligning the
first ends of each piece, of the second layer and
the second ends of each piece of the second layer
such that the ridges and air channels of the second
layer are positioned along the longitudinal axis>;
and placing the bottom surface of the first layer on
the top surface of the second layer in the aligned
position to form the landing surface.
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In accordance with still yet another aspect: of
the present invention there is provided a method of
making a landing surface block having a longitudinal
axis and a transverse axis including a first layer
formed from a single piece of compressible material
having top and bottom surfaces, the bottom surface
of the top layer having a plurality of ridges
oriented along the transverse axis of the landing
surface and defining a plurality of spaces
therebetween, comprising: placing the first layer
on a second layer having top and bottom surfaces,
the top surface of the second layer having a
plurality of ridges and air channels formed between
the ridges and positioned along the longitudinal.
axis.
The foregoing has outlined some of the more
pertinent objects of the present invention. These
objects should be construed to be merely
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illustrative of some of the more prominent features
and applications of the invention. Many other
beneficial results can be attained by applying the
disclosed invention in a different manner or
modifying the invention as will be described.
Accordingly, other objects and a fuller
understanding of the invention may be had by
referring to the following Detailed Description of
the preferred embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the
present invention and the advantages thereof,
reference should be made to the following Detailed
Description taken in connection with the
accompanying drawings in which:
FIGURE 1 is a perspective view of a contoured
landing surface in accordance with the present
invention;
FIGURE 2 is an end view of a landing surface
and illustrates the contoured structure having air
channels therebetween in accordance with the present
invention;
FIGURE 3 is a side view of a contoured landing
surface system illustrating the point of impact in
accordance with the present invention; and
FIGURES 4A-4F illustrate a method of making a
single density landing surface in accordance with
the present invention.
Similar reference characters refer to similar
,, 30 parts throughout the several views of the drawings.
DETAILED DESCRIPTION
n The present invention provides a single density
contoured landing surface system suitable for a
variety of uses. Preferably, the landing surface is
used for athletic events. In the moat preferred
embodiment, the landing surface includes a
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multi-layer structure having a single density and is
used as high jump and pole vault landing pits for
controlling deceleration and ensuring a smooth and
safe landing for the athlete. The contoured system
of the present invention, however, is not limited to
high jump and pole vault landing pits. The system
may also be utilized during other activities such as
landing surfaces for stunt work.
The present invention provides smooth, safe
landings by precisely matching landing surface or
pit density to the force generated by an athlete's
rapidly falling body. The landing surface thus
accounts for variations in mass, velocity and
surface area at the point of impact on an. individual
basis. FIGURE 1 shows a landing surface prepared in
accordance with the invention, preferably having a
single density. A finished block 10 generally
includes a top layer 12, a bottom layer 14 and at
least one middle layer 16. The foam is preferably
polyurethane and is commercially available from
several sources. In alternative embodiments,
further padding or support is provided by
incorporating additional middle layers 16 or by
omitting the top or bottom layer. Each of the
layers 12, 14 and 16 are provided with a plurality
of ridges 18, which form air channels or baffles 20
therebetween. The air channels 20 divide each of
the foam layers, such that the finished product has
a waffle-like construction.
Preferably, the top layer 12 is approximately
,.
six inches thick and air channels 20 are positioned
to extend in an upward direction approximately three
inches from the bottom surface of top layer 12..
This construction is particularly advantageous when
the landing surface of the present invention is used
as a pole vault or high jump landing pit. The most
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basic construction includes a two-layer structure
having a six-inch top layer and a twelve inch bottom
layer, for a total of 18 inches of thickness. In a
preferred embodiment, at least one ridge and one air
channel are positioned within every twelve inches of
each surface which has ridges and air channels
formed thereon. While not meant to :be limiting the
following constructions are also suitable for use in
accordance with the present invention: (1) a 24-inch
thickness having two six-inch layers and a
twelve-inch layer between, (2) a 30-inch thickness
having a top layer of six inches and two 12-inch
layers underneath (as illustrated in FIGURE 3), and
(3) a 36-inch thickness including si:~-inch top and
bottom layers and two 12-inch layers positioned
therebetween.
Prior art constructions generally employ a
thicker top layer, thereby requiring more
compression by the user prior to reaching the first
air pocket. In contrast, the present invention only
requires compression of about three :inches of top
layer 12 prior to contacting the firat air pocket.
In accordance with the present :invention, the
air channels 20 form a network which includes
generally smaller and more numerous air channels
than those traditionally utilized. 'this is
important since smaller, more numerous air channels
having a volume V for air displacement will displace
air at a greater velocity than a structure, such as
a honeycomb construction, which has t:he same volume
V but with larger, less numerous openings. As a
result of the increased velocity, the displaced air
is forced upwards at a greater pressure to provide
a
greater force against the athlete's body upon
impact. Consequently, the athlete does not
experience the level of stress as with the larger
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air channel constructions. The ability to displace
air more accurately provides a landing surface which
is capable of accommodating a wider range of users,
while still maintaining a safe and comfortable -
landing surface. This is based on the functioning
of the landing surface primarily based on air
movement rather than on foam density.
Reference is now had to FIGURE 2 in which one
end of a foam pad construction prepared in
accordance with the present invention is
illustrated. As shown in FIGURE 2, the air channels
and ridges 18 of each layer 12, 14 and 16 form a
waffle-like construction. The block 10 is typically
enclosed on the bottom and four sides in a
15 protective casing or cover 22 formed of fabric such
as PVC coated vinyl fabric, manufactured by and
available from Cooley, Incorporated. The PVC coated
vinyl fabric is a solid, non-breathable material
having a base cloth which has been coated on both
20 sides to prevent problems associated with moisture.
The base cloth is a polyester fabric having a 5.3
oz. high tenacity 1000 denier which provides better
results than the standard 840 denier nylon since
nylon absorbs ten times the moisture that polyester
will absorb at room temperature. Consequently, the
strength of nylon is reduced by about 15% while the
polyester remains unaffected. Additionally, while
nylon has good initial strength, the coating
process, the exposure to sunlight and moisture
seriously reduce the integrity of the nylon. A ,
cover 22, such as PVC vinyl fabric, is less likely
to stretch out of shape or be affected by
ultraviolet light (sunlight degradation). Thus, the
cover 22 will maintain its original appearance
longer and retain more of its performance integrity
over extended use.
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The top of cover 22 is preferably the only
surface which is constructed of a breathable
material. For example, a vinyl coated polyester
fabric, such as Phifertex, is suitable for use in
accordance with the present invention and is
available from Phifer Wire Products, Incorporated.
Phifertex~"' is a breathable weaved mesh material
having 350 open air space and which cleans easily
with mild detergent and water. Phifertex is
particularly well-suited for use in the present
invention since each weave strand is individually
coated and then weaved into a mesh. The mesh is
then oven treated to bond weave cross points,
thereby forming a tear-resistant, extremely durable
fabric. Additionally, the PVC coating resists
mildew. Further, chemical additives in the vinyl
resist fading due to ultraviolet exposure. One of
the advantages of using a construction wherein t:he
only breathable surface is the top surface is that
upon impact, air is displaced and forced in an
upward direction such that excess air is expelled
through the top surface. As discussed above, this
provides additional comfort to the user rather than
having air expelled through the side or bottom
surfaces.
The preferred embodiment of the present
invention is illustrated in FIGURE 3 which shows the
landing surface having a cover 22 with the side of
the cover 22 removed for purposes of illustration.
Generally, cover 22 encases all four sides of the
block in addition to the top and bottom surfaces.
The landing surface functions as follows.
Preferably, a 2 inch top pad (not shown in FIGURE 3)
is placed on top of the cover 22 such that the
majority of force is transferred through the top pad
onto the base unit as shown in FIGURE 3. As force
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is imparted on the base unit or landing surface, top
layer 12 is compressed in a direction shown by arrow .
30 in response to the user's weight, velocity and
impact surface area. The compression of layer 12
forces air out of air channels 20 positioned along
the sides or the transverse axis of layer 12. The
expelled air, which is forced outward and upward
with a greater velocity and pressure as discussed
above, then circulates to the top of top layer 12
and acts as an additional cushion to the athlete.
Excess air is then expelled outside cover 22 through
the breathable top material or other vents in the
cover.
If the mass, velocity and/or impact surface
area are great enough, top layer 12 will further
compress in a direction as indicated by arrow 30 and
contact middle layer 16 such that air is also
expelled from channels 20 of the top and bottom
surfaces of middle layer 16 located at the
longitudinal ends of the block. Similarly, further
force~imparted upon the block will cause the block
to compress and contact bottom layer 14, thereby
forcing air out of channels 20 located in the
transverse sides of the block on the top and bottom
surfaces of bottom layer 14. Thus, the landing
surface made in accordance with the present
invention accommodates and automatically adapts to
the individual user to eliminate "jarring" and
"bottoming out" effects without any manual
adjustments.
Although not required, the construction and
placement of the layers used in accordance with the
present invention enables the use of a single
density foam system. This provides a distinct '
advantage over the prior art which includes filling
a pit with a combination of different density foam
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sections. Another distinct advantage of the present
invention over the prior art is the distribution of
force of the athlete upon impact over the entire
construction. A landing surface having a prior art
honeycomb construction results in the athlete
feeling the entire force of the foam thickness upon
impact. Moreover, as the foam structure degrades,
voids in the landing surface are experienced,
thereby resulting in reduced comfort and even injury.
In contrast, the construction of the present
invention distributes force upon impact over the
entire construction~and permits air to be expelled
in directions 90 to one another to cushion the
fall. Moreover, it has been discovered that an
initial loan deflection (ILD), which measures the
pressure necessary to compress or penetrate a 4"
foam sample 1", of 24 psi provides unexpectedly
smooth and comfortable landings.
For example, the single density contoured
system of the present invention is more efficient in
controlling deceleration. Furthermore, when two or
more types of foam are laminated together using
prior art techniques, the product life is frequently
reduced. The present invention, however, avoids
this shortcoming by combining the single density
block with the unique network of air passages
channeled in two different directions. Thus, a
consistently controlled deceleration is thereby
achieved.
Further, landing surfaces constructed in
accordance with the invention reduce fatigue
experienced by athletes who use the pits for
repetitious landings in a short period of time.
This is attributable to the reduced stress
("jarring" or "bottoming out") experienced when
using the landing surface of the present invention,
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thereby resulting in increased comfort and safety of
the user. As a result, athletes can train longer
and perform more repetitions before requiring a rest.
FIGURES 4A-4F illustrate a method of making a
contoured landing surface system in accordance with
the present invention. FIGURE 4A shows an uncut
block 10, while FIGURE 4B depicts the block 10 cut
with contours 32 to form bottom layer 14, top layer
12 and middle layer 16.
FIGURES 4C and 4D illustrate the layers
separated from one another, such that contours 32
form ridges 18 and air channels 20 in each layer.
FIGURES 4C and 4D also show middle layer 16, which
has ridges 18 and air channels 20 on both the top
and bottom surfaces, divided into middle pieces 28
such that each middle piece 28 has a first end 24
and a second end 26. In accordance with the present
invention, middle pieces 28 are then rotated such
that first ends 24 and second ends 26 contact each
other and are each aligned adjacent to each other.
The middle pieces 28 are then adhered to one another
using adhesive or the like.
Layers 12, 14 and 16 are then joined together
by placing the bottom of the middle layer 16 on top
of the bottom layer 14 and then placing the top
layer 12 over the top of the middle layer 16 as
shown in FIGURE 4E. The middle layer 16 thereby
forms a waffle-like construction with the top and
bottom layers.
While the first or top layer has ridges and air ,
channels formed only on the bottom surface thereof,
the second layer and any additional layers ,
preferably include ridges 18 and air channels 20 on
both top and bottom surfaces thereof. The layers
are then attached and preferably adhered to one
another. In the preferred embodiment, the adhesive
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is applied where the foam ridges contact each
other. While not meant to be limiting, one type of
adhesive which is suitable for use in the present
invention is a hot melt adhesive manufactured by
United Resin Products, Incorporated, which is
available as Part No. 80-8392. This adhesive,
having a viscosity of 500 cps. at 350 F, is applied
to the structure at 375 F.
In an alternative embodiment of making a
landing surface in accordance with the present
invention, one or more layers are placed on top of
each other in the following manner. Each layer has
a plurality of ridges 18 formed thereon such that a
plurality of air channels 20 are formed between each
ridge 18. The ridges and air channels of one layer
are positioned along a longitudinal axis while the
. ridges and air channels of the adjacent layer or
layers are positioned along the transverse axis such
that the landing surface, once formed, has a
waffle-like construction, as discussed above. In
this manner, it is possible to form a contoured
landing surface having a single or multi-density
layered structure which is still capable of
functioning primarily based on air displacement.
It should be appreciated by those skilled in
the art that the specific embodiments disclosed
above may be readily utilized as a basis for
modifying or designing other structures for carrying
out the same purposes of the present invention. For
example, it is within the scope of the invention to
prepare a landing surface having a waffle-like
construction which is suitable for use as evacuation
safety devices from airplanes and the like. Such
devices may be used as supplements to existing
safety devices, in which case the landing surfaces
may be stored on the ground for easy .access during
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an emergency. Alternatively, the device may be
compressed and stored on board an aircraft for
immediate access. Similarly, the landing surface is
adaptable for use for evacuating the lower floors of
a burning building or for other emergencies
requiring emergency evacuations. It should also be
realized by those skilled in the art that such
equivalent constructions do not depart from the
spirit and scope of the invention as set forth in
the appended claims.
20
30
